The present invention relates to a bookbinding apparatus and an image forming system having the bookbinding apparatus and more particularly to an art for adhering a plurality of sheets of paper with an adhesive, thereby preparing a booklet.
In the field of light printing, for example, an image forming system is in wide use, in which an image forming apparatus having a high-speed image forming performance such as an electrophotographic image forming apparatus and a bookbinding apparatus are connected, thereby performing a process from printing to bookbinding at one step, and preparing a booklet.
Such an image forming system, unlike a conventional general book manufacturing step for executing separately the printing step and bookbinding step, although the printing speed and bookbinding speed are low, is comprehensively a highly efficient image forming system having an advantage that print contents can be changed easily as required and is used as a POD (print on demand) system.
The characteristic of the POD system is that it is highly flexible such that print contents can be changed as required, thus by the POD system, for example from a booklet of ten and several pages to a booklet of several hundreds pages and various kinds of sheets of paper are used.
On the other hand, the POD system is often installed in an environment such as an office, so that it is required to be small. Therefore, in a bookbinding apparatus composing the system, as a binding step capable of forming booklets by a comparatively simple binding step, a binding step for binding sheets of paper using an adhesive is often used.
Such a bookbinding apparatus is disclosed in Patent Documents 1 and 2.
In Patent Document 1, by changing the height of a scraper roller for controlling the thickness of an adhesive layer coated and formed on the spine of the booklet in correspondence with the thickness of a booklet to be prepared, the amount of coating of adhesive is controlled in correspondence with the thickness of the booklet.
In Patent Document 2, an adhesive is coated by a coating roller moving along the spine of a booklet in the longitudinal direction thereof and by selection of the rotational direction of the coating roller, the amount of coating corresponding to the thickness of the booklet is controlled.
As the POD system, in order to coat uniformly an adhesive of an amount of coating corresponding to a booklet with a greatly different thickness and moreover to respond quickly as required, the coating amount control by changing the height of the scraper roller and changing the rotational direction of the coating roller like Patent Documents 1 and 2 is not sufficient.
Patent Document 1: Unexamined Japanese Patent Application Publication No. 2000-168265
Patent Document 2: Unexamined Japanese Patent Application Publication No. 2004-209753